Carriage-spring



J. M. FORREST.

Garriage-Spring.

No. 26,981. Patented Jan. 31, 1860.

Inventor,

AM. PHOTO-THO, C0. N.Y- (OSBURNE'S PRDCESS.)

range of strains than the springs in common JOHN M. FORREST, OF

NORFOLK, VIRGINIA.

CARRIAGE-SPRING.

Specification of Letters Patent No.

To all whom it may concern:

Be it known that I, JOHN M. FORREST, of the city and county of Norfolk, in the State of Virginia, have invented certain Improvements in Carriage-Springs; and I do hereby declare the following to be a correct description of the same, reference being had to the accompanying drawings, in which- Figure 1, is a side elevation of my improved spring, and Fig. 2, is a top View or plan of the same showing the mode of its attachment to a vehicle.

The same part is marked by the same letter of reference in both the figures.

The nature of my invention consists in the mode hereinafter more particularly set forth of forming and connecting the springs of vehicles so as to make them accommodate themselves to the varying weights imposed, retaining their elasticity through a greater use.

The ordinary springs are liable to the objection that if they are soft and elastic under a light weight, they become rigid or nearly so under a heavy one; and, on the other hand, if they are made stiff enough to bear heavy weights they are not sufliciently elastic under light ones.

The object of my invention is to remove this difficulty by making a spring which is suflieiently elastic under both light and heavy weights, while I secure other incidental advantages.

To enable others to make and use my improved spring I will proceed to describe its construction and mode of attachment, referring to the drawings. 1

The spring 8 I make of any number of plates that may be desirable, and give it the form shown in side view in Fig. 1. This may be described as a cyma recta, with its lower end turned out to a horizontal line, and produced until it passes under the lower 26,981, dated January 31, 1860.

curve of the cyma. Two springs of this character are placed on each axletree, and are united by a connecting bar 5. They are attached to the axletree by screws or clamps at d, and to the connecting bar I) by the toggle joints 0 which allow slight lateral play to the bar. The bar I) is forked at its ends, as shown in Fig. 2, 5 being the tines of the fork, between which the spring 8 passes up as clearly shown in the figures. The body of the vehicle is attached to the connecting bar at the points 5 on both branches of the fork of the bar. Then a light weight is placed on the springs formed and arranged in this way, the whole length of the spring from the point a; to the point 0 is in operation; but when a heavy weight is applied the spring is depressed until the lower curve 0 of the cyma comes in contact with the horizontal portion of the spring below it. In this position only that portion between the points 0 and c is in operation, and the spring has that increased stiffness which the increase of Weight requires. Thus my spring is perfectly self adjusting. It is obvious that the springs may be reversed on the axles, so that their upper ends shall be directed inward instead of outward as in the drawing, or that they may be placed at right angles to the aXletrees, without affecting the principle of my invention.

Having thus fully described my invention, what I claim and desire to secure by Letters Patent, is-

A carriage spring constructed arranged and operating substantially in the manner described.

The above specification signed and witnessed this ninth day of January A. D.

J. M. FORREST. IVitnesses:

CHAS. F. STANSBURY, EDW. F. BROWN. 

